Why has the sr AWD version the same HP insteed of the RWD sr version?

[AlexE1971]

The sr AWD and the RWD has both 266 HP. The AWD has an extra motor in front. Why the same HP?

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[RonTCat]

The sr AWD and the RWD has both 266 HP. The AWD has an extra motor in front. Why the same HP?

You are battery limited, not motor capacity limited.

 

[AlexE1971]

You are battery limited, not motor capacity limited.

Ok, thanks for your reaction!

 

[generaltso]

It does have more torque though because that extra motor gives it more twisting force.

 

[Wildthing]

I finally understood that the battery limits the HP but what I still don't understand is why is a 78 kWh battery is a limiting factor? When you compare the competition, most have 75-80 kWh batteries and has much more HP and torque than the Mach-E (Volvo, Polestar, Tesla, Jaguar, etc.).

The Model 3 Performance is believed to have around 450 horsepower despite a 75 kWh battery.
Polestar/Volvo also has a 78 kWh battery but they get 408 HP (and 487 lb-ft of torque). I understand that they have a more powerful motor but with 428 lb-ft of torque, I don't understand why the Mach-E has only 266 HP

So the real question is why the Mach-E is so limited with a 78 kWh battery? The math doesn't work

 

[SnBGC]

The sr AWD and the RWD has both 266 HP. The AWD has an extra motor in front. Why the same HP?

Not sure. I think it's just an omission on their charts. They show the hp and torque increase for the Extended Range AWD so you would think the SR AWD would have a similar increase? In the charts for the AWD SR, the torque figures are increased but not the HP? The two are linked so you can't have an increase in one without a change in the other (all else being equal).

 

[AlexE1971]

Not sure. I think it's just an omission on their charts. They show the hp and torque increase for the Extended Range AWD so you would think the SR AWD would have a similar increase? In the charts for the AWD SR, the torque figures are increased but not the HP? The two are linked so you can't have an increase in one without a change in the other (all else being equal).

so i think the HP of the sr AWD must be 322. That make sense. 266 on the rear motor and 56 on the front motor.

er RWD is 290 HP on the rear. The front motor on the er AWD is also 56 HP and Total of HP is 346 HP of this model.

 

[RonTCat]

I finally understood that the battery limits the HP but what I still don't understand is why is a 78 kWh battery is a limiting factor? When you compare the competition, most have 75-80 kWh batteries and has much more HP and torque than the Mach-E (Volvo, Polestar, Tesla, Jaguar, etc.).

The Model 3 Performance is believed to have around 450 horsepower despite a 75 kWh battery.
Polestar/Volvo also has a 78 kWh battery but they get 408 HP (and 487 lb-ft of torque). I understand that they have a more powerful motor but with 428 lb-ft of torque, I don't understand why the Mach-E has only 266 HP

So the real question is why the Mach-E is so limited with a 78 kWh battery? The math doesn't work

kWh is a measure of energy, not power.

 

[Wildthing]

kWh is a measure of energy, not power.

I know that but I try to understand why with 2 motors instead of one the standard range AWD Mach-E has the same horsepower than the RWD standard range Mach-E (and even less horsepower than the RWD long range Mach-E that has only one motor).

 

[SnBGC]

so i think the HP of the sr AWD must be 322. That make sense. 266 on the rear motor and 56 on the front motor.

er RWD is 290 HP on the rear. The front motor on the er AWD is also 56 HP and Total of HP is 346 HP of this model.

I think it is about a 50 hp increase on standard range battery. So about 316 hp total?

 

[AlexE1971]

I think it is about a 50 hp increase on standard range battery. So about 316 hp total?

sr RWD = 266 HP
Er RWD = 290 HP

that’s 24 HP more.

er AWD = 346 HP minus 24 HP is 322 HP. 266 +56 HP (front motor) is also 322 HP.

Torque of the sr AWD and the er AWD are the same.....

 

[AlexE1971]

sr RWD = 266 HP
Er RWD = 290 HP

that’s 24 HP more.

er AWD = 346 HP minus 24 HP is 322 HP. 266 +56 HP (front motor) is also 322 HP.

Torque of the sr AWD and the er AWD are the same.....

so the HP of the sr AWD must be 322 HP.

 

[BlueMach]

I finally understood that the battery limits the HP but what I still don't understand is why is a 78 kWh battery is a limiting factor? When you compare the competition, most have 75-80 kWh batteries and has much more HP and torque than the Mach-E (Volvo, Polestar, Tesla, Jaguar, etc.).

The Model 3 Performance is believed to have around 450 horsepower despite a 75 kWh battery.
Polestar/Volvo also has a 78 kWh battery but they get 408 HP (and 487 lb-ft of torque). I understand that they have a more powerful motor but with 428 lb-ft of torque, I don't understand why the Mach-E has only 266 HP

So the real question is why the Mach-E is so limited with a 78 kWh battery? The math doesn't work

It's not the "78 kWh" part that limits it. It's the "288 cells" part.

The Standard Range pack is a "3P96S" configuration, with 3 parallel banks of 96 cells in series, for a total of 288 cells.
The Extended Range pack is a "4P94S" with 4 parallel banks of 94 cells in series, for a total of 376 cells.

We can assume the same cells are used in both packs, so the cells have a common maximum discharge current.

The SR pack has {CELL DISCHARGE POWER} * 288 cells = 190 kW pack discharge limit
The ER pack has {CELL DISCHARGE POWER} * 376 cells = ? kW discharge limit

Assuming 190 kW is the limit, and assuming the system is at 400V that would yield:

190,000W/400V = 475A
475A / 288 cells = 1.65A /cell

If we assume that's right, we can then get the theoretical discharge limit for the ER pack:

1.65A * 376 cells = 620 A
620A * 400V = 248,000W

Looking at the Mach-E ER AWD, the total system power is: 248 kW.

We know the PDU is capable of 210 kW (ER RWD). We know there are two SDUs, a GT and a non-GT. Neither SDU's power has been directly confirmed, but adding the non-GT SDU to the ER pack only bumps system power by 38 kW, so either that's the world's smallest SDU, or Ford is throttling the ER AWD.

Why would that be the case if the GT's ER battery can support 342 kW peak discharge? That's an interesting question. My theories are that:

1.) Ford is upgrading the cell inside the GT pack
2.) that the actual current limit is not the cell, but the internal wiring inside the pack, which would be upgraded for the GT
and/or
3.) that Ford is software limiting the non-GT pack, or possibly any combination of the three.

This is just rough "non-scientific" math to get a sense of why things are this way, but they're things we can easily assume from the public specs sheet, and a healthy bit of inference and speculation.

 

[SnBGC]

sr RWD = 266 HP
Er RWD = 290 HP

that’s 24 HP more.

er AWD = 346 HP minus 24 HP is 322 HP. 266 +56 HP (front motor) is also 322 HP.

Torque of the sr AWD and the er AWD are the same.....

so the HP of the sr AWD must be 322 HP.

I see your logic and it makes sense.....except the standard battery isn't able to provide the same amount of watts to the front motor compared to the larger battery. When I do the math, it comes out to about 50.6 hp for the front motor.

 

[ARK]

To add to what @BlueMach said, it is possible that even if there is a chance that there isn't a technical limitation here with the SR AWD, Ford may be limiting the motors or effectively detuning them because Ford does not want the SR AWD to be almost as fast or match or, who knows, even exceed the ER AWD (i.e. the First Edition model) - the SR AWD after all weighs hundreds of pounds less than the ER AWD.

Manufacturers have sometimes done this sort of thing to better differentiate their engine line up on a model and make paying for the upgraded engine (or I suppose motor here) more attractive. No idea if this was done here, but I suppose it is possible when based on the published numbers, the 0-60 time for the SR AWD is 5.2 seconds and the equivalent time for the ER AWD is not leaps and bounds higher at 4.8 seconds.

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